// 前端获取cookie的函数
function getCookie(c_name) {
    if (document.cookie.length > 0) {
        c_start = document.cookie.indexOf(c_name + "=")
        if (c_start !== -1) {
            c_start = c_start + c_name.length + 1
            c_end = document.cookie.indexOf(";", c_start)
            if (c_end === -1) c_end = document.cookie.length
            return unescape(document.cookie.substring(c_start, c_end))
        }
    }
    return ""
}